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- Proceedings of the Physico-Mathematical Society of Japan. 3rd Series
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Volume 60, Issue 1
Displaying 1-50 of 54 articles from this issue
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Akira Onuki, Hiraku Nishimori1991 Volume 60 Issue 1 Pages 1-4
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSAs their sizes grow, domains that are harder than the matrix change their shapes from spheres to other shapes to cancel anisotropic elastic fields produced by other domains. Harder domains then tend to be elastically isotropic, and the adjusted shapes are ellipsoids in the dilute case. Eshelby’s interaction exists only among spheres and disappears after such shape adjustment. Furthermore, shape changes of softer domains are much more drastic and take place even in single precipitate cases. These conclusions generally hold under the coherent condition, whether the order parameter is conserved or not.View full abstractDownload PDF (584K) -
Shigeo Kida1991 Volume 60 Issue 1 Pages 5-8
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe logarithm of the breakdown coefficient εr⁄εl, εr being the mean energy dissipation rate averaged over a sphere of radius r is shown, under a similarity assumption, to obey a stable distribution, the characteristic function of which is given by \varphi(z|r⁄l)=(r⁄l)(μ⁄2α−2)[iz−(zeiπ⁄2)α], where μ>0 and 0<α≤2. The scaling exponent of the p-th order moment of the energy dissipation rate is calculated to be μp=μ(pα−p)⁄(2α−2), which is in excellent agreement with the experiments (Anselmet et al. 1984) when the intermittency parameter is μ=0.20 and the characteristic exponent of the distribution is α=1.65. The probability density function of εr diverges as 1/εr(−ln εr)α+1 at the origin and decreases as exp [−A(ln εr)α⁄(α−1)], where A>0, as ε→∞. The present results include the log-normal theory for α=2 and coincide with the prediction of μp due to the β-model in the limit α→0.View full abstractDownload PDF (420K) -
Akira Yoshizawa1991 Volume 60 Issue 1 Pages 9-12
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSA subgrid-scale (SGS) model is proposed to enable the numerical simulation of magnetohydrodynamic (MHD) turbulence at very high kinetic and magnetic Reynolds numbers in fusion plasma physics and astro/geophysics. The model supplements the SGS energy dissipation process with the aid of the SGS turbulent viscosity, the SGS anomalous resistivity, etc., which are written in terms of the grid-scale magnetic field and velocity.View full abstractDownload PDF (536K) -
Yukio Noda, Hirofumi Kasatani1991 Volume 60 Issue 1 Pages 13-16
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSStructural data of K3H(SO4)2 and K3D(SO4)2 reported by Noda et al. [J. Phys. Soc. Jpn. 59 (1990) 2809 and ibid. 3249] are precisely examined in order to investigate the possible origin of the isotope effect in a hydrogen bond material. The SO4 molecule is slightly distorted from a regular tetrahedron. The distortion is explained by the displacement of the sulfur atom as well as that of the oxygen atom which is in charge of forming the hydrogen bond. The size of the SO4 molecule in the D-compound is slightly larger than that in the H-compound, but the difference seems to be marginally small. The major geometrical difference is only seen in the hydrogen bond length ROO. In addition, electron transfer between hydrogen and oxygen atoms with opposite directions was found. The difference of the ionicity of H and D atoms is considered to be the origin of the difference of the bond length ROO.View full abstractDownload PDF (580K) -
Akira Inaba, Hideaki Chihara1991 Volume 60 Issue 1 Pages 17-20
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSHeat capacity measurements have been made to study the phase transitions occuring in the monolayer of CH3Cl physically adsorbed on the surface of graphite. It reveals the existence of two different two-dimensional solid phases depending on the coverage: the low-density phase (ca. 5 molecule/nm2) melts at 120 K; the high-density phase (ca. 7 molecule/nm2) melts at 146 K. There is a coexistence region in between, where the melting point of the high-density phase becomes lower with a decrease in the coverage. The high-density solid undergoes an order-disorder phase transition at 128 K accompanied by the excess entropy of approximately R ln 2, which suggests the possibility that a random head-tail disordering occurs in the admolecules. An anomaly in the fluid phase is also found near the full coverage of the monolayer, which may indicate the presence of some ordered fluid just above the melting point.View full abstractDownload PDF (532K) -
Hisatomo Harima, Akira Yanase1991 Volume 60 Issue 1 Pages 21-24
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSVery recently, the de Haas-van Alphen effect in the heavy fermion superconductor CeCu2Si2 was observed by M. Hunt et al. We report the band structure calculation and Fermi surface of CeCu2Si2 within the local density approximation. The slender arms of the hole sheet can explain the angular dependence of the measurements. The mass enhancement factor is up to 6 in the measured field.View full abstractDownload PDF (524K) -
Yasutami Takada, Takafumi Kita1991 Volume 60 Issue 1 Pages 25-28
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSBased on the Pauli-Feynman theorem for the ground-state energy, a new self-consistency relation is established between the correlation energy and the momentum distribution function in a many-body system. Similar relations concerning the correlation functions are also derived. Those general relations are applied to the one-dimensional Hubbard model and are found quite useful.View full abstractDownload PDF (556K) -
Takashi Yanagisawa1991 Volume 60 Issue 1 Pages 29-32
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSWe study the two-impurity Anderson model by the exact diagonalization method in small systems and the variational method. With varying of the exchange coupling J between two impurities, we evaluate the staggered susceptibility χs to investigate the competition between the Kondo effect and the RKKY interaction effect. The staggered susceptibility in our calculations shows no anomalous behavior in contrast to the recent numerical renormalization group calculations. In order to study this further, we introduce the even-parity-mixing Anderson model. This model appears to show singularities in χs and the ground-state energy at a point J=Jc. We show that at this point, the ground state changes suddenly; the localized spins form a triplet for J<Jc and a singlet for J>Jc. In the original two-impurity Anderson model, a crossover occurs around Jc without singularity.View full abstractDownload PDF (560K) -
Yoshimasa Isawa1991 Volume 60 Issue 1 Pages 33-36
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSIn terms of the Wigner distribution function, we investigate an idealized one-dimensional model in which scattering potentials in the conducting channel, leads, and reservoirs are treated as a whole without separating them. We find that the electron density oscillates around the scattering potential, and the two-terminal conductance G in our model is quantized, G=2e2⁄h, independent of the transmission coefficient of the electron wave.View full abstractDownload PDF (508K) -
Masaaki Yoshikawa, Kazuyoshi Yoshimura, Takashi Imai, Yutaka Ueda, Hir ...1991 Volume 60 Issue 1 Pages 37-40
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSNuclear resonance of Cu in Pb2Sr2Y1−xCaxCu3O8+δ with x=0 and 0.5 has been observed under zero external magnetic field. For the nonsuperconducting sample (x=0), we have observed both the nuclear quadrupole resonance (NQR) and the antiferromagnetic nuclear resonance (AFNR), each of which is due to two inequivalent Cu sites. On the other hand, two sets of NQR signals were observed in the superconducting sample (x=0.5), indicating the disappearance of antiferromagnetic ordering. The temperature dependence of the nuclear spin-lattice relaxation rate, 1⁄T1, for the NQR signal in the superconducting sample is also reported.View full abstractDownload PDF (520K) -
Fumitaka Matsubara, Taketoshi Iyota, Sakari Inawashiro1991 Volume 60 Issue 1 Pages 41-44
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSAn efficient method of simulating the Heisenberg model is proposed taking into account the spin dynamics, and applied to a short-range Heisenberg spin glass on a simple cubic lattice. Our method shows a drastic reduction in relaxation times and clearly reveals the vanishing of the order parameter q and the divergence of the susceptibility according to the Curie law as the temperature is decreased.View full abstractDownload PDF (460K) -
Hiroyuki Mashiyama, Hironobu Kasano, Toshihisa Yamaguchi1991 Volume 60 Issue 1 Pages 45-48
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe structural phase transitions of K2ZnBr4 and K2CoBr4 are investigated by means of X-ray scattering. The transition from the room-temperature α phase to the high-temperature β phase takes place at about 200°C. It is found that the β phase is an incommensurate one with the modulation wave vector q=(1⁄3−δ)c*, which is followed by a normal phase of Pmcn above 288°C (Zn-salt) or 282°C (Co-salt). If the β phase is supercooled to below room temperature, then the crystal is a commensurate phase with q=1⁄3c*. With increasing temperature, the commensurate-incommensurate phase transition is observed at 5°C in Zn-salt. The transition sequence of normal, incommensurate and commensurate phases is quite common in A2XY4-type incommensurate materials, though the α phase is very different from others.View full abstractDownload PDF (456K) -
Takao Yamazaki, Akio Kotani1991 Volume 60 Issue 1 Pages 49-52
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSSystematic analysis is carried out for 4f core photoemission spectra of actinide oxides AcO2 for Ac=Th∼Bk, using the impurity Anderson model including the exchange interaction J between 5f electrons. The effect of J is important in explaining the observed photoemission spectra, especially for PuO2, AmO2 and CmO2. It is shown that PuO2 and BkO2 are strongly mixed valence compounds.View full abstractDownload PDF (500K) -
Takami Tohyama, Sadamichi Maekawa1991 Volume 60 Issue 1 Pages 53-56
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe optical conductivity in high Tc Cu oxides is theoretically examined by diagonalizing exactly the Hamiltonian of a Cu4O13 cluster and using the Kubo formula. We show how the optical conductivity caused by the charge transfer from Cu to O ions in the insulator is depressed and how the low-energy conductivity of the Drude type emerges when electron- and hole-carriers are introduced into the CuO2 plane.View full abstractDownload PDF (552K) -
Haruo Saito, Toshio Hyodo1991 Volume 60 Issue 1 Pages 57-60
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSPositron lifetime spectra in KI have been measured in the temperature range between 12 K and 295 K. Large changes of the spectrum due to the transition of the ortho-positronium from a free state to a self-trapped state have been observed. A new long-lived component has been found at low temperatures and attributed to the irradiation-induced positive ion vacancy.View full abstractDownload PDF (496K) -
Minoru Itoh, Satoshi Hashimoto, Nobuhito Ohno, Ken-ichi Kan’no1991 Volume 60 Issue 1 Pages 61-64
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe interrelation between the intrinsic emission bands of NaI and KI has been examined by observing changes of luminescence spectra and their decay profiles in mixed Na1−xKxI crystals at 10 K. As x is increased from 0 to 1, the π emission band of NaI changes continuously into the σ emission band of KI. Furthermore, the decay component with a long lifetime (∼100 ns) diminishes, while the component with a short lifetime (∼1.0 ns) intensifies. An emission band changing into the π band of KI appears above x=0.95. It is concluded that the self-trapped exciton (STE) responsible for the π band of NaI corresponds to that for the σ band, rather than the π band, of KI. Lattice configurations of initial states for these emission bands are briefly discussed in connection with the recent off-center model of the STE.View full abstractDownload PDF (500K) -
Shuji Obata1991 Volume 60 Issue 1 Pages 65-76
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSA new method is developed for calculating the electronic structures of condensed matter in a real-space formulation based on the LCAO approximation. Using the Householder method, a matrix of a secular equation is partially transformed into a band matrix. In the early steps of this transformation, recurrent terms appear in the band matrix. These terms are changed into complex quantities. The site Green’s functions are then calculated from the resulting smaller matrix. By changing the renormalization order of the sites in a central cluster, the site Green’s functions are easily obtained. The electronic structures can be calculated from these site Green functions. A graphic calculation method is introduced to perform the renormalisation processes and an example is shown using a square lattice.View full abstractDownload PDF (1108K) -
Isamu Nakata1991 Volume 60 Issue 1 Pages 77-81
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSNonlinear electromagnetic waves in a ferromagnet in the presence of an external magnetic field are investigated by using a nonlinear perturbation method. In the lowest order of perturbation, it is found that the system of equations for the electromagnetic waves in a ferromagnet can be reduced to the modified Korteweg-de Vries equation. In the case of steady propagation this equation can be integrated to give a solution in closed form, which exhibits a solitary wave. Two kinds of solitary wave are found to be possible.View full abstractDownload PDF (492K) -
Kazuyoshi Yoshimura, Shinsuke Watanabe1991 Volume 60 Issue 1 Pages 82-87
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSAn envelope soliton in a nonlinear lattice has been studied theoretically and numerically. First, the nonlinear Schrödinger equation describing a lattice wave with large wave number is derived and then the equation of motion for the nonlinear lattice is solved numerically taking the one envelope soliton solution of the nonlinear Schrödinger equation as an initial wave. It is shown that the envelope soliton with zero group velocity exists stably in the lattice and that the frequency of carrier wave is above the cut-off frequency of the lattice. An intrinsic localized mode in the nonlinear lattice developed by Takeno is pointed out to be the envelope soliton with zero group velocity.View full abstractDownload PDF (604K) -
Hiroshi Fujikawa, Mitsugu Matsushita1991 Volume 60 Issue 1 Pages 88-94
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSA Bacillus subtilis strain is found to grow through the diffusion-limited aggregation (DLA) process on agar plates. The organism is spotted on the agar plate containing a low concentration of peptone as a single nutrient and incubated at 35°C. The colony pattern grown on the plate surface is self-similar with the fractal dimension of 1.73±0.02. Bacterial DLA branches are shown to grow in a concentration field of nutrient from the fact that they grow predominantly in the direction of higher nutrient concentration. The colonial morphology varies with the nutrient and agar concentrations of an agar plate, including DLA, a round type, dense branching morphology (DBM), and a spreading without openings. Two neighboring colonies repulse each other in DLA and DBM types only. On an agar plate containing glycerol the colony becomes remarkably round, quite different from the DLA morphology.View full abstractDownload PDF (2476K) -
Makoto Katori, Norio Konno1991 Volume 60 Issue 1 Pages 95-99
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSAn upper bound for the survival probability of infected region σd,λ(A), (A⊂Zd), is presented for the contact process. The bound depends not only on the cardinality number |A| but also on the number of neighboring pairs of sites in A. It may correspond to Krinsky’s bound using the Bethe approximation for the Ising models. The present result can be viewed as a generalization of Griffeath’s bound for an order parameter ρ1,λ(≡σ1,λ({x})) in the one-dimensional system to the survival probabilities for all A in arbitrary dimensions.View full abstractDownload PDF (564K) -
Nicolo’ Arena, Sebastiano Cavallaro, Alberto D’arrigo, Gio ...1991 Volume 60 Issue 1 Pages 100-106
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe reaction 7Li(d, αα)n was studied by detecting αα coincidences with a forward-forward and a forward-backward geometry at 1.4, 2.1 and 2.5 MeV incident deuteron energies. The analysis of the αα bidimensional spectra allowed us to isolate the first excited 5He state from other reaction products. The values of (3.8±0.3) MeV and of (3.1±0.5) MeV for the excitation energy and width of this state were found, respectively.View full abstractDownload PDF (644K) -
Yûzo Asano, Shigeki Mori, Misao Sakano, Kazuaki Katoh, Kenjiro K ...1991 Volume 60 Issue 1 Pages 107-113
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSFormation cross sections of product nuclides in the nuclear reactions of Ti, Fe, Co, Ni, Cu, and Zn targets by 500-MeV protons were measured with a Ge(Li) γ-ray spectrometer. The measured cross sections in the mass range between A≅40 and A≅AT−4 were used in the charge-dispersion analysis, where AT is the mass number of the target nucleus. The N⁄Z ratio of the charge-dispersion peak was found to be consistent with those obtained in the same mass range of spallation products in the nuclear reactions of the same medium-mass targets with 12-GeV protons. The mass-yield curve falls sharply with decreasing masses of product nuclides in contrast to relatively flat distributions at higher energies.View full abstractDownload PDF (796K) -
C. W. Wang, E. K. Lin, S. W. Hsu, Y. C. Hsu1991 Volume 60 Issue 1 Pages 114-121
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe gamma-radiation following the reactions 27Al(α, γ)31P, 27Al(α, pγ)30Si, 27Al(α, α′γ)27Al and 27Al(α, nγ)30P have been measured. Excitation functions were obtained at 90° in the energy range Eα=3.4–6.4 MeV for selected regions of γ-ray energies with a high resolution HpGe detector and a large volume NaI(Tl) scintillator. In all, about 300 resonances were observed and the corresponding excitation energies (Ex=12–15 MeV) of the compound system 31P were determined. The obtained level density in this region was compared with the calculation of a statistical compound nucleus theory.View full abstractDownload PDF (756K) -
Shigeru Morita, Kunizo Ohkubo, Tsuneo Amano, Kazuo Kawahata, Kuniaki M ...1991 Volume 60 Issue 1 Pages 122-128
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSNonthermal spectra of full titanium Kα lines have been successfully measured from plasmas with suprathermal electrons generated by lower-hybrid waves in the JIPPT-IIU tokamak using a compact and wide-band crystal spectrometer. Increase in total intensities of the all Kα lines has been observed at decreasing electron densities below 7×1012 cm−3 and strong Kα emissions from partially M-shell-ionized ions are found. These results suggest the spectra are strongly characterized by the nonthermal plasma. Analysis is carried out under assumptions of some radial profiles of the suprathermal electrons. As a result, the spectra can be explained by the inner-shell ionization due to the suprathermal electrons.View full abstractDownload PDF (884K) -
Huzio Nakano, Naoki Yamamoto, Hatsuo Kimura1991 Volume 60 Issue 1 Pages 129-137
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSIn contrast with conventional theories of optical activity, in which the change of electromagnetic fields over the correlation length in an optically active molecule is neglected so that the fields are regarded as uniform over that length, the present paper takes into account the effect of this change of the fields in the case of light with wave length not long enough compared to the correlation length. In result, certain new dependences upon the frequency of light comes about in circular dichroism (CD) as well as optical rotatory dispersion (ORD). For some simple models, the frequency dependences of ORD and CD are shown schematically.View full abstractDownload PDF (688K) -
Gajendra K. Johri, Shashi K. Pathak1991 Volume 60 Issue 1 Pages 138-140
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSMicrowave linewidths of the JK 0, 0→1, 0 rotational line of methyl bromide (CH3 81Br) broadened by OCS, C6H6, CCl4 have been calculated using an interpolation scheme recommended by Johri and Mehrotra for strong Collisions and considering dominant interactions in each case. A comparison is also given with the measured and calculated linewidth parameters using the Anderson-Tsao-Curnutte (ATC) theory and the Murphy-Boggs (MB) theory. It is found that for strong collisions in the cases considered, the interpolation scheme used in this work explains the linewidth parameter within the range of 25–30%.View full abstractDownload PDF (288K) -
Koichi Shimoda1991 Volume 60 Issue 1 Pages 141-145
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe scalar theory of Gaussian beams is an approximation to describe narrow beams of light. A vectorial analysis is required to describe the electromagnetic fields in the focal region with a small spot size. Maxwell’s equations are solved to obtain the longitudinal as well as the transversal components of field vectors in a beam of light propagating along an axis. Solutions of the electromagnetic fields of either the plane-polarized-electric (and magnetic) or the transeverse-electric (and magnetic) modes are expressed in terms of Hermite-Gaussian functions. Magnitudes of the longitudinal field components in these modes are evaluated in particular.View full abstractDownload PDF (508K) -
Makoto Umeki1991 Volume 60 Issue 1 Pages 146-167
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSNonlinear Schrödinger equation with complex-conjugate-type (parametric) forcing and linear damping is studied both analytically and numerically. Bifurcations of stationary and time-dependent solutions are investigated. A periodic motion arising via a Hopf bifurcation of the cnoidal solution explains well the soliton-oscillation phenomena of water wave in a vertically forced long container discovered by Wu et al. The analogy is pointed out in an explicit way between the mode competition of surface waves in a container and the soliton-oscillation. The existence of spatiotemporal chaotic states is illustrated by numerical simulations.View full abstractDownload PDF (1795K) -
Yasuo Saruyama1991 Volume 60 Issue 1 Pages 168-179
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe unperiodic quasi-lattice structure has been constructed of the helical polymer molecules starting from the interaction potentials of the molecules. The process of the construction is explained in detail. The construction is carried out according to the local equivalence postulate which requires that all pairs of the nearest neighbor molecules in the system are packed in the equivalent way. The construction is based on the symmetry of the molecules and not dependent on the shape of the potential function of each material. The obtained quasi-lattice structure is the ground state of the system. Both the one dimensionally unperiodic structure and the two dimensionally unperiodic structure are found. Geometric features of the quasi-lattice structure are investigated.View full abstractDownload PDF (1472K) -
Hiroyuki Mashiyama1991 Volume 60 Issue 1 Pages 180-187
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe structures of the commensurate phase III and IV of Potassium Tetrachlorocobaltate was determined by single-crystal X-ray diffractometry at room temperature and 134 K, respectively. The room-temperature structure is the same as the orthorhombic modification determined by Vermin, Verschoor and IJdo (Acta Crystallogr. B32 (1976) 3325). The symmetry lowering with the phase transition at 142 K is induced by a rotation of one kind of the CoCl4 tetrahedra, which have rather large thermal parameters at room temperature, about the c-axis with accompanying a translation along the a-axis.View full abstractDownload PDF (860K) -
Kazuhiro Hanazawa, Masaru Komukae, Toshio Osaka, Yasuharu Makita, Masa ...1991 Volume 60 Issue 1 Pages 188-195
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSElastic, thermal and dielectric measurements of TlH2PO4 were carried out in a temperature range covering the upper phase transition point at 357 K. The specific heat shows a λ-type anomaly associated with the upper phase transition of second order and yields the transition entropy ΔS=1.46 J/mol·K. The elastic stiffness c55 among cii (i=1, 2, …, 6) determined from the ultrasonic velocity data at a frequency of 10 MHz shows a large anomaly with a tendency to approach zero in value at the upper phase transition point. It was shown that the upper, ferroelastic phase transition is caused by an instability of the B2g transverse acoustic mode, and the elastic, thermal and dielectric behaviours near the ferroelastic phase transition point can be reasonably explained by a phenomenological theory.View full abstractDownload PDF (780K) -
Akira Terai, Yoshiyuki Ono1991 Volume 60 Issue 1 Pages 196-203
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe dynamics of a charged soliton pinned by an impurity in the presence of an electric field is numerically studied by using Su-Schrieffer-Heeger’s model for trans-polyacetylene. The field is introduced in terms of a time-dependent vector potential which is included in the Hamiltonian in the form of a phase of the transfer integral. The time-dependent Schrödinger equation for the electronic wave functions and the equation of motion for the lattice displacements are numerically integrated in a self-consistent way. When the field is lower than a certain threshold value, the soliton remains trapped and oscillates periodically around the impurity position. As the field is increased, the time period of the oscillation becomes longer. When the field exceeds the threshold value, the soliton is depinned and begins to move in one direction. The threshold field is estimated to be 105–106 V/cm, which is in rough agreement with the value obtained in experiments on polyacetylene lightly doped with AsF5.View full abstractDownload PDF (1108K) -
Yorihiko Tsunoda1991 Volume 60 Issue 1 Pages 204-211
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSA periodic shear wave (PSW), observed in γ-Fe precipitates in Cu at low temperature, was studied by X-ray diffraction under compressive uniaxial stress within an elastic limit. Although the lattice structure has an orthorhombic symmetry, for the applied stress, each Fe precipitate behaves as if it possessed a tetragonal symmetry which is accomplished through the PSW formation. This indicates that the PSW is regarded as an intrinsic incommensurate lattice wave although the wavelength is mainly determined by the mesoscopic veriable, i.e., the size of the precipitates. The PSW is well explained by a new model of a precursor modulated phase in the martensitic transformation based on the nonlinear and nonlocal elastic continuum theory.View full abstractDownload PDF (912K) -
Yoshihiro Ishibashi1991 Volume 60 Issue 1 Pages 212-218
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSUtilizing a one-dimensional atomic chain model, commensurate structures have been discussed. It has turned out that the structure with the odd period N must have the homogeneous (k=0) component of the order parameter. The pinning energy for commensurate structures is discussed on the basis of obtained structures.View full abstractDownload PDF (660K) -
Mamoru Yamashita1991 Volume 60 Issue 1 Pages 219-226
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSA model with coupling between the orientation of molecule and the interlayer spacing is introduced to investigate a mechanism of the first order phase transition found in a certain antiferroelectric liquid crystal. By the decimation transformation, the model is reduced to an Ising model of S=1 with biquadratic exchange interaction and zero field splitting, in which the first order phase transition is shown to occur for the case of reasonable values of parameters appearing in the model.View full abstractDownload PDF (796K) -
Yoshimi Tsuchiya1991 Volume 60 Issue 1 Pages 227-234
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSThe high energy γ-ray attenuation and sound velocity have been measured to investigate the bonding nature and structural changes in liquid Ge–Te system. The results have been used to deduce the molar volume and adiabatic compressibility. The volume for Te rich alloys around the eutectic composition shows anomalous increase as the liquidus temperature is approached. Correspondingly the thermal expansion coefficient and adiabatic compressibility show very sharp extrema at around 400°C, which indicates that rapid structural changes occur in the liquid.
At high temperatures, the composition dependences of the volume and compressibility show small positive deviation from the linear interpolations where anomalies in the magnetic susceptibility and electrical properties have been found.View full abstractDownload PDF (752K) -
Migaku Oda1991 Volume 60 Issue 1 Pages 235-244
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSMagnetic behaviors and their effects on the conductivity are examined in the Néel state (TN\simeq210 K) of La2CuO4 single crystals. The magnetization jump at a field-induced weak ferromagnetic (WF) transition and the critical field exhibit the same T-dependence as the sublattice moment. The magnetoresistance ΔR, observed at the WF transition, takes a small positive value down to ∼110 K (T*), while for T\lesssimT*, ΔR is negative and its magnitude increases drastically with lowering T. At T*, a magnetic transition is also observed; it is accompanied by a large decrease of hopping conductivity due to an enhancement of Anderson localization. It is shown that the large negative ΔR for T\lesssimT* is due to the increase of the carrier mobility, which arises from the fact that the enhancement of Anderson localization below T* is largely suppressed by the spin structure change at the WF transition.View full abstractDownload PDF (1160K) -
Michisuke Kobayashi, Fuyuki Shimojo, Fumio Tachibana, Hideo Okazaki1991 Volume 60 Issue 1 Pages 245-253
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSA computer simulation by a molecular dynamics method at constant volume has been performed to a model system which is composed of accumulating two different ionic conductors: …AgI–Ag2S–AgI–Ag2S…. Along the c-axis (z-axis), AgI-parts are compressed and Ag2S-parts are stretched. About 3% of Ag ions in Ag2S-parts have been transfered to AgI-parts. The self-diffusion coefficient of Ag ions in AgI-parts decreases by 40–50% compared with that in a single AgI-system, while the diffusion coefficient of Ag ions in Ag2S-parts increases by 30% compared with that in a single Ag2S-system. The ionic conductivity of the superlattice-system is larger than that of either material of the AgI-system or Ag2S-system. The calculation suggests the possibility of the existence of a new material which has a larger ionic conductivity.View full abstractDownload PDF (1048K) -
Ki-ichi Nakamura1991 Volume 60 Issue 1 Pages 254-264
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSA computer simulation using particles has been performed to investigate the mechanism of tremendous low-frequency current noise associated with the acoustoelectric instability in piezoelectric semiconductors. Electrons are trapped in the troughs of the piezopotential due to the acoustic wave amplified from the thermal background and are forced to move with the sound velocity. However, the trapped electrons can transfer to the neighboring troughs not by external random force, but by intrinsic nonlinear dynamics. This is the origin of the tremendous acoustoelectric current noise.View full abstractDownload PDF (1012K) -
Sanshiro Sako1991 Volume 60 Issue 1 Pages 265-269
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSIn the metallic small particle, the spin relaxation on surface mainly contributes to the conduction electron spin resonance (CESR) linewidth because a small particle has a large rate of surface to volume. We can measure the spin relaxation probability on surface of a metal by investigating the size dependence of residual linewidths of CESR at low temperature. By this method, we obtained the spin relaxation probability ε=(2.3±0.3)×10−4 and ε=(6.6±0.5)×10−5 for Mg and Al respectively.View full abstractDownload PDF (888K) -
Yoshiyuki Ono, Tomi Ohtsuki, Bernhard Kramer1991 Volume 60 Issue 1 Pages 270-279
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSElectronic states in a two dimensional random system with a perpendicular strong magnetic field are analyzed by using a model Hamiltonian matrix which has random elements reflecting the characteristics of the random potential such as the correlation length. The random matrix model is suitable for numerical calculations and has advantages compared to preparing the random potential by distributing impurities particularly when discussing correlated potential. As an example, the fractal dimensionality of extended states in the lowest Landau band is considered. It is found that the extended states have multifractal properties. The results are compared with those obtained through the random potential model.View full abstractDownload PDF (1212K) -
Fumihiro Matsukura, Y\={u}ichi Tazuke, Tomonao Miyadai1991 Volume 60 Issue 1 Pages 280-287
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSIn order to understand spin glass freezing process we measured ac-susceptibilities and thermoremanent magnetizations in Fe0.05TiS2 and analyzed the results by considering the distribution of relaxation times. We adopted two distribution functions. One is a conventional modified Debye distribution function and the other is a rectangular distribution function. We conclude that the latter is more appropriate and its parameter follows a power law, being consistent with previous results.View full abstractDownload PDF (816K) -
Shunsuke Takano, Eiji Kita, Kiiti Siratori, Kay Kohn, Shigeyuki Kimura ...1991 Volume 60 Issue 1 Pages 288-293
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSThe magnetoelectric effect, which was second order in the electric field, was measured in a YIG single crystal synthesized with traveling floating zone method in the temperature range between 77 K and 240 K. Contrary to the first order effect, the signal due to the second order effect was independent of the electric field during cooling of the specimen from room temperature. However, the temperature dependence was very similar: both effect decreased sharply around 125 K, although a small part of the second order effect remained at higher temperature. The signal at 77 K was analysed on the mechanism of the electric field dependence of the magnetic anisotropy. It is suggested that the electric field induced magnetic anisotropy, which is second order in the magnetization direction, plays an important role, as well as the change of the ordinary K1 term in the cubic phase.View full abstractDownload PDF (660K) -
Susumu Hirakata, Midori Tanaka, Kay Kohn, Eiji Kita, Kiiti Siratori, S ...1991 Volume 60 Issue 1 Pages 294-299
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSMössbauer effect and dielectric constant measurements were performed with single crystal specimens of Y3Fe5O12 (YIG), to obtain information as to a possible phase transition at 125 K, where the first order magnetoelectric effect appears. Mössbauer spectra for various conditions were compared, and the results indicated that there was no detectable difference between the spectra above and below the supposed transition point and between those cooled to 77 K with and without electric field. This means that the lattice distortion at the phase transition, if any, is too small to affect the Mössbauer spectrum or the disappearance of the center of symmetry was due to some other mechanism than structural phase transition. The results of dielectric measurements was also negative for the existence of a structural phase transition.View full abstractDownload PDF (632K) -
Yoshikazu Nishihara, Shinji Ogawa1991 Volume 60 Issue 1 Pages 300-303
Published: January 15, 1991
Released on J-STAGE: May 29, 2007
JOURNAL RESTRICTED ACCESSMagnetization of Y2Ni7 and Mössbauer spectra of 57Fe doped in Y2Ni7 are measured. The paramagnetic susceptibility of Y2Ni7 above 150 K follows the Curie-Weiss law. The ratio of paramagnetic moment to ferromagnetic moment of 0.077 μB per nickel atom is 6, revealing an itinerant-electron character of ferromagetism in Y2Ni7. The hyperfine field of 57Fe doped in Y2Ni7 is ∼190 kOe, which lies on a smooth interpolation curve between the hyperfine field in Y2Ni17 and that in YNi3 as a function of yttrium concentration in contrast with a re-entrant behavior of a magnetic moment of nickel atom in the compounds.View full abstractDownload PDF (384K) -
Hideo Takeuchi, Hiroshi Ebisu, Masanori Arakawa1991 Volume 60 Issue 1 Pages 304-312
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSEPR measurements for the substitutional Fe3+ ions in layered perovskite-type Rb2CdF4 crystals have been made at room temperatures using a X-band spectrometer. A tetragonal spectrum is ascribed to an uncompensated Fe3+ centre. An orthorhombic spectrum is analysed by separating the fine structure terms into uniaxial terms and a cubic one. Obtained uniaxial parameters are well compared to those for the other tetragonal Fe3+ centres. By the analysis, the orthorhombic centre is ascribed to a Fe3+ ion associated with a nearest-Cd2+ vacancy. The fine structure parameters are analysed further by the Newman’s superposition model to obtain metal-ligand distances. Results are discussed together with those for the Cr3+ and Gd3+ centres in A2MF4 crystals.View full abstractDownload PDF (1000K) -
Ping He1991 Volume 60 Issue 1 Pages 313-323
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSTemperature and frequency dependent dielectric responses of Rb1−x[N(H1−yDy)4]x(H1−yDy)2PO4 (0.25≤x≤0.75, 0≤y≤1.0) have been measured from 4.2 K to 300 K and between 1 kHz and 1 GHz. The glass-like dielectric dispersion was found in the low temperature region. The relaxation time τ has been confirmed to follow the Vogel-Fulcher law, τ=τ0 exp [E⁄(T−T0)], with a temperature independent Gaussian distribution of energy parameter E. Pronounced effect of deuteration was found in the dynamical dielectric properties. On the contrary, there is no obvious x dependence in the dynamical properties. Little difference was observed in the dielectric dispersions along the a- and c-axes. These results indicate that proton motion in the O–H…O bond has decisive role in the glass-like behavior.View full abstractDownload PDF (1112K) -
Kazuo Gesi, Roland Machet, René Perret, Bernard Jannot1991 Volume 60 Issue 1 Pages 324-329
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSSingle crystals of the solid solution system {N(CH3)4}2ZnCl4−xBrx have been prepared in a low x region, and the effect of hydrostatic pressure on the phase transitions were measured for x=0.2 and 0.3. The normal-to-incommensurate phase transition temperatures increase linearly with increasing pressure with the rates of 0.126 K/MPa and 0.129 K/MPa for x=0.2 and 0.3 crystals, respectively. The ferroelectric III phase disappears at about 60 MPa for x=0.2 crystal. On the other hand, phase III is not observed for the x=0.3 crystal both at 0 pressure and at high pressures. The II–IV or III–IV transition temperatures also increases with increasing pressure with the rates of 0.162 K/MPa and 0.153 k/MPa for x=0.2 and 0.3 crystals, respectively. The p-T phase diagrams of the mixed crystals are compared with that of pure {N(CH3)4}2ZnCl4, and discussed.View full abstractDownload PDF (600K) -
Hitoshi Hirashima, Kunitsugu Soda1991 Volume 60 Issue 1 Pages 330-339
Published: January 15, 1991
Released on J-STAGE: June 01, 2007
JOURNAL RESTRICTED ACCESSMaking a least-squares fit of a formula derived in our previous work to published data on the transfer free energy of amino acids from octanol to water, atomic transfer parameters have been estimated for sixteen nonionic amino acids. Among the carbon atoms, those having a partial charge of 0.18 electron charge or more and β-carbon atoms of side chains, were found to have a significantly lower hydrophobicity than other aliphatic and aromatic carbon atoms. The most plausible model for classifying all constituent atoms into six groups is proposed: sulfur, oxygen, nitrogen, aliphatic carbon, aromatic carbon, and partially charged carbon and/or β-carbon. Considering the conformational distribution of amino acids, and evaluating separately the intramolecular interaction energy and the solvation energy of each amino acid, are shown to be essential for estimating accurate atomic transfer parameters.View full abstractDownload PDF (1252K)